Promise of the Samurai Youkai
by TheCyborgMerc
Summary: {Disclaimer:I do not own the characters or Art} This is a tale of an Samurai who became a Youkai named Soma Motoyasu who is after someone important to him that inhabits Gensokyo. (OC Faceclaim:Gintoki)
1. Chapter 0 - Prologue

**Promise of the Yokai – Prologue**

" _Where am I? It's so dark..."_

A male's voice echoed in the darkness surrounding him, it was cold it was like he was getting frozen alive, however while the male felt the cold only getting worse a voice could be heard, it wasn't like anything he ever heard before it echoed in the darkness like if it was something divine talking to him, little did he know that wasn't the case at all.

 _"I'm going to ask you a question… Do you have a last wish?"_

The male's eyes widened with the revelation, he wasn't sure what was going on, but he tried to keep his composure and replied.

 _"I'm dying?.. I guess i am.. but here it goes, i know this will sound quite weird.. but could you make a grave for me?"_

The voice went silent for a few seconds, before speaking yet again louder this time and it seemed closer.

 _"Hmm.. that's an odd request.."_

The male nodded weakly, the voice then said however this time it was closer his ear, which startled him however he was sure of what he wanted.

 _"Very well, I'll grant your final wish, however before your spirit leaves your body, tell me what's your name?..."_

The male closed his eyes and spoke in a weak tone of voice a few seconds before his spirit would be sent to the netherworld.

"… _Nishio… and promise me you'll do that…."_

The voice became silent while the male departed to the Netherworld

however the male's body became warm yet again, however this time it wasn't his own soul who inhabited it, his frail human body became something else, a yokai's in fact the voice who spoke to the young man was actually a voice of a yokai who haunted a nearby sword who was hidden from the village, this yokai's name was Soma Motoyasu, a fallen samurai.  
Once his eyes opened he saw a forest that was close to the human village it wasn't deep inside the forest but it was quite close to the area where Yokai mostly wandered nearby, the ground was full of dry and dead leaves , the sword on front of him, on the place he died in that arduous battle, he doesn't remember how he died since it was long ago, once he examined his new body, he was wearing a white yukata with a pair of getas, next he started to wonder how did the male most likely die, it was quite odd, however he speculated that he probably died of sickness most likely because there wasn't any signs of fighting, but there was blood on the ground, next he approached his katana he reached towards it, grabbing it by the sheath, the male then took a deep breath and began to gather some nearby stones and made a improvised grave while kneed down, once he was done he stood up the male began to wander into the deeper woods with his sword in hand, his Getas making a faint leaf crushing noise each time he took a step, the wind making the leaves rustle in the forest as well, making his light blue hair waved in the wind, after he walked for a bit he couldn't help but wonder what had changed from the past it's been like 100 years or more, a few minutes after the male stopped walking and mumbled to himself.

 _"A lot has happened.. my sword isn't a normal one anymore as well.. I can feel some dark energy coming out from it.. could it be?.."_

The male went silent, he knew something was off about his sword, however he didn't know why it had this aura coming out of it, next the male began to head deeper inside the forest, but he had something on his mind, mostly because the young adult told him to promise him he would do his last wish, it's another promise he failed to keep long ago, after all its what made him into a Yokai in the first place, while he kept walking the male said in a serious tone of voice it wasn't clear what he felt was anger or sorrow.

"I'll find you, i'll search every corner of this place."

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This is my first story, i welcome constructive criticism and feel free to ask any questions about the plot if interested.


	2. Chapter 1

**An Ordinary Magician and a Shine Maiden - Chapter 1**

"It's morning already?"

The blonde magician mumbled to herself, she just had woken up, she stretched and yawned and mumbled to herself while she looked outside trough one of her windows inside her house, the house was extremely messy like always, piles of books everywhere and a lot of random stuff that she 'borrowed' lying on the table.

"Today is a great day for a walk, maybe I could gather some mushrooms."

Next she would get her witch hat and her broom along with her trusted mini-Hakkero going outside afterwards, closing the door behind her walking deeper into the woods, searching for her mushrooms however, that doesn't mean that was the only intention the Magician had she was actually hoping something would try to attack her so she could blow stuff up.

"Alright, Let's start searching for those mushrooms ze."

While Marisa wandered through the woods searching for her mushrooms, she saw a male with long dark purple hair wearing a white yukata and a pair of getas with a katana in his hand, to Marisa he looked quite weird, especially because she noticed he wasn't human, it was quite obvious since most people know a human male from the village wouldn't get this deep inside the woods, most of them are afraid to go deep into the forest, after a while she mumbled to herself while she watched the male closely.

"Who's that? I'm sure he is not human."

Marisa decided to approach the male, once she was closer to him she said in a loud tone of voice catching his attention while he gripped his sword tightly since that startled him, since she came out of nowhere and he wasn't able to notice her.

"Hey, are ya a Youkai? you better don't cause trouble or I'll kick your ass."

The male turned around the girl with the smaller stature, his eyes had slits and they were red now since the body began to adapt to the new owner the process was rather fast, however the male wasn't dumb enough to pose any threat to this girl, he simply knew he would lose instantly mostly because he didn't want to fight unless needed and his body wasn't ready for any type of fight, so he replied in educated tone of voice.

"Yes I'm a Youkai, do not worry miss, I won't cause any problems to the human village, I'm just passing by.. "

Marisa was kind of disappointed by what he said, since she wanted to fight something, but since the Youkai didn't cause trouble she let him go unharmed at least for now, a few seconds after that the female said.

"Ya, just watch out, don't do anything stupid."

The male nodded before asking in the same educated tone of voice, he was quite interested in this young girl, mostly because not a lot of humans would livethis deep inside the forest.

"Before I continue walking, mind telling me your name?"

Marisa lifted her eyebrow, she didn't know what was his intention with this but she replied in the same informal manner she always does.

"I'm Marisa, what yer name?"

The male then replied while he looked at the female while he smiled a little.

"My name Soma, It's nice to meet you Marisa-san."

Marisa closed her eyes and waved her hand up and down while she lifted her arm a little, then she spoke while she looked at the male Youkai.

"Ya ya, I know da ze."

She seemed to not like formalities very much, Soma respected that, even though he was a Youkai she didn't demonstrate any fear whatsoever a few seconds after that Soma said while he turned around and began to walk away.

"If you'll excuse me."

Once the male walked away Marisa mumbled to herself while she reached out towards the back of her head rubbing her neck while she seemed very surprised that the Youkai didn't attack her.

"That's a weird Youkai... well let's go back to collecting mushrooms ze."

While the female went back to what she was doing the male walked by himself, silently hoping he would find the person who he is looking for, the promise he made long ago needed to be fulfilled, after a while of walking the male said after stopping and holding tightly onto his weapon, gritting his teeth in anger and sorrow yet again, while closing his eyes.

"I'll kill her..."

After that the male's grip loosened while he opened his eyes however, before he continued walk he heard a loud and serious voice behind him, it was a female's but once he turned around he saw a Reimu with her loose black hair, wearing a red ribbon on her head along with two matching red tubes on her side locks, she was small compared to the male, but that didn't mean the male thought he was stronger than her, once he saw the purification rod on her hand he knew that she was a shrine maiden since it was quite obvious, however before he could speak Reimu, she shot danmaku at the Youkai, he barely dodged it however once he was on the floor Reimu walked up to him and pointed at him with her purification Rod, having her shoot first and ask questions later attitude like always, the male was sweating cold, one mess up and he would be sent to the afterlife most likely at least on his eyes that's what going to happen. however, the Miko heard him saying that he'll kill someone that made him very suspicious so she asked while she looked at him with her red eyes, she was very intimidating actually but she knew she didn't know the whole story so she decided to hear him out.

"Who you said you're going to kill?"

The male sighed and then replied with a somewhat nervous yet firm tone of voice.

"It's another Youkai, it's a long history..."

Reimu approached him and then kneed down before saying in a sincere yet somewhat indifferent way.

"Tell me the story, is this youkai dangerous?"

She was odd indeed, she wasn't respectful towards him but wasn't rude as well which was a odd thing for a shrine maiden to do, the male knew that things had changed from back then, but this was very surprising to him.

"Well, you see... I'm not human anymore but I do not remember what happened but I'm sure I actually died in the past, but I do remember one thing I promised while I died, Someone in our group became a Youkai from their own volition, this was a little before Gensokyo was away sealed for some reason I did not go to the afterlife, I suspect she has something to do with this, I do not only wish to make her pay for what she did, I want to know why as well, you can do whatever you wish to me after that, I do not care."

Reimu closed her eyes before folding her arms, once she opened her eyes the female explained to the male who had no idea how he was rebirthed as a Youkai.

"Youkai tend to appear once a human dies while feeling some intense emotion, despite another ways as well, well to put it in simple words, it wasn't your fault you died and turned into a youkai, however this person... once they become a Youkai from their own volition, they need to get exterminated, it is the ultimate sin, so for that reason, I'll help you exterminate this Youkai, do not think I'm helping you because I respect you or something like that, I'm just interested in exterminating her."

The male nodded and then he replied while, taking a deep breath he knew if she joined him she would be a powerful ally, he knew he would need some help to defeat his enemy, he was a very weird youkai as well, since accepted help from a human.

"Very well, I don't have any complaints about that..."

Reimu lifted her eyebrow and then she replied to the male while she was also surprised that the Youkai accepted, she knew this was quite unusual, Youkai didn't like help especially from humans, but he seemed to not care.

"You're a weird Youkai, accepting help from a human."

The male shook his head and then he said while crossing his arms, turning around while he looked at her from the corner of his eye, then he replied.

"To me both Youkai and Humans are equal, they don't need to be antagonistic with each other, to me they are people trying to get by, they are not superior to the other in my eyes."

The male sighed after he put out his opinion to Reimu, she was quite surprised that a Youkai would say something like that, she found him a bit interesting because of his ideals, but she decided to question it with her own opinion.

"I see, well that won't happen… Humans and Youkai won't get along by how much you try, the Youkai need to kill humans in order to survive, they cannot live together, but I do agree that no one is better than the other."

Soma closed his eyes and rubbed the back of his head before replying to the shrine maiden, what he said was very interesting to the shrine maiden.

"I never said they can live together, but they are more alike than you realize."

Reimu sighed and then waved her hand at the male and then changed the topic, she needed to find the Youkai who betrayed Soma, so she asked.

"Anyways, this Youkai you want to kill… Do you have any idea where she is?"

The male shook his head and then he replied to Reimu, she seemed a bit annoyed that he didn't know.

"I don't know, I know she will come after me if she knows I'm alive, she will probably attack me with her aberrations."

Reimu then asked once he said about these Aberrations, she had no idea what they were so she decided to ask the male about it.

"Aberrations? What do you mean?"

The male closed his eyes and gripped his sword tightly while he began to explain about it to the miko, it was something hard to explain but he would put it in simple words.

"Basically, she can create beings however these beings she creates they are not alive nor dead they are they are just mindless organic puppets that do her bidding, some of them may look human but do not be fooled by their appearance, their body is more resistant than a human's and they can fight using weapons like bows and swords and magic, but if you hit them enough they go back to their original state and they stop moving, she isn't the type to obey rules, if she gets bored enough the human village will get destroyed, luckily they might be weak to seals like Youkai are."

Reimu nodded and realized that most likely this Unknown Youkai wouldn't battle using the rules, she most like would send these puppets to kill the person or capture them, she knew this Youkai would cause trouble in the human village in the future and that gave her even more motive to finish off this Youkai, then she replied to the male while she sighed.

"We need to deal with—"

Suddenly Reimu was interrupted by a magic blast making a tree fall down on the floor between both of them making leaves fly up in the air with the impact, once she looked at the direction of where it was shot from she saw a bizarre looking human he looked like one, but he couldn't stand on his feet very well and he walked very slowly once Soma saw that thing as well he drew his sword while it tried to shoot a magic blast at Soma, however before he could do that Reimu her yin yang orbs to attack it, once the magic blast hit the puppet, it fell down it was already defeated, however that wasn't the only one.

"Damn! there are more coming this way!"

Reimu sighed, she knew she would be able to destroy these pushovers with no problem, however she found quite strange the Youkai wasn't defending himself, he was actually shaking and sweating cold, next she asked.

"Are you afraid?!... Snap out of it!"

A shadow appeared on Soma's eyes, while he looked at the monsters who just appeared, the part she didn't know is that the Unknown Youkai was playing mind games with Soma , in fact these other puppets were identical to his partners in the past, next Soma said in a upset tone of voice.

"They look like my partners…"

Reimu then yelled yet again her orbs circling around her, making him snap out of it.

"Hey snap out of it! They are nothing more than mindless puppets, they are not your comrades!"

His sorrow transformed into anger, next the male said while he held the hilt of his Katana tightly.

"You're right… sorry I nearly lost myself there, however I won't forgive her for using them to make petty mind games."

The male rushed at them and sliced through 7 puppets, each one of them with a single swing, his rage was nothing more than fuel for his strength, that is when suddenly a giant laser was shot diagonally from the sky, fortunately only he nearly got hit by it since the blast was very close to him, destroying the rest of the puppets, when Soma and Reimu looked at the direction that the laser was fired, it was no one else than Marisa, once they looked at her she said in the same tone of voice like always while sitting on her broom.

"What you and the weird Youkai doing in the woods?"

Reimu lowered her guard since all puppets were destroyed, the female then replied while she folded her arms holding her purification rod with her right hand.

"Apparently, there is a Youkai who is quite dangerous and wants to stop it, it's a long story."

Marisa then smiled and then replied to the Miko while she landed on the ground with her broom in hand, however the Youkai wasn't looking at their direction at all and they didn't notice that, however he felt a strange presence close to them, but the two girls didn't notice that something was about to show up behind her.

"Well I'm in, let's go find this Youkai da ze."

A few seconds after Marisa said that a loud roar could be heard very close to them, once both girls looked around they saw Soma holding his sword in hand while he looked at a big creature with white fur all over its body and with horns on its head sharp twisted teeth and yellow cat like eyes holding a tree in its left hand his nails were very large and sharp as well , it seemed one of the puppets however this one was different his body worked perfectly, and an powerful aura surrounded it, this was no ordinary puppet, it was an actual monster made by the Youkai they were hunting meaning she could create powerful beasts, but it was unclear to them if she could do this very often, once Marisa and Reimu saw the monster the magician stated.

"Damn that is ugly, let's beat it up da ze."

The monster roared at them yet again while it gripped the trunk tightly, getting ready to attack the male and the two girls.

* * *

Well, this is the actual first chapter, hope you guys enjoy it, well i do still accept constructive criticism and forgive me if i forgot something about the Touhou verse in this chapter, i'm kinda new to the series but i did do some research before doing this.


	3. Chapter 2

Chapter 2 - Questions

Soma held his sword tightly in hands while the monster tried to hit him with very slow claw swipes, they were easy to dodge but the impact they made each time they hit the ground it made a big shockwave throwing dust in the air, while the monster got distracted by Soma, Marisa pointed her Mini-Hakkero at the beast and charged up a master spark while she aimed it at the beast.

"Soma, I would get out of there if I were you take this! Love Sign, Master Spark! "

then she fired it once soma jumped away from where the blast would hit the beast was hit by it, however even though it managed to hit it, it only made some burns on the beast since she didn't have time to charge it completely and shooting a full blast at this distance would be very stupid since the explosion would hit her and her comrades as well, however Reimu had a plan while both of them were distracting the beast she would use her own attack, she knew she needed to do her best to defeat this monster since it managed to tank a halfway charged master spark, while her orbs began to circle yet again around her she yelled before started preparing her attack.

"Keep it busy!"

Soma nodded and then rushed at the beast and began to slash at it's face, it managed to get a few cuts on it's face while Marisa did the majority of the damage they were able to do to the beast, however Marisa found weird that he wasn't using his powers to fight this beast it was unclear if he wasn't using his powers because he couldn't or because he didn't want to do it, however Soma was slashing away at the monster and it kept it busy so he was still doing his job.

"This thing is resistant!"

Reimu was nearly done preparing her attack, however the beast managed to land a hit against Soma making him fly against a tree however the impact seemed not to do too much damage to the male, he was able to stand up afterwards despite having a few light bruises on his face and arms, however before the white beast could do anything else, Reimu yelled and Soma jumped in the air next to Marisa and then flew to a safer distance .

"Spirit sign, Fantasy Seal!"

Next a giant Yin yang orb fell on the beast utterly obliterating it, making near trees break in half and making a crater on the ground, Soma and Marisa shielded themselves from the wind from the impact of Reimu's attack once the battle was finally over Reimu flew over at the Youkai and the magician and said.

"Let's go, this needs to end soon before this gets worse..."

Soma crossed his arms and nodded, however Marisa looked towards the north, she actually saw someone fly out of sight in the woods, disappearing afterwards, it was unclear who it was.

"Soma I might have seen yer Yokai."

The male looked at Marisa in the eyes and then he flew after the person she saw, Reimu however noticed something that they didn't so she explained.

"I don't think she would risk coming here to see us fight… Maybe she needs to be close to control these puppets…"

Marisa seemed to agree with idea because it made sense, even though Youkai are very unpredictable, there was a large chance she needed to be close to be able to control these puppets, Reimu then said.

"Let's go after Soma."

The both females then flew at the same direction as while he had gone way further than the both girls, however Soma didn't find for who they were searching for, but however he knew it was her, next the male landed on the ground while Reimu and Marisa still flew after him, while he searched around the forest for a bit, a few minutes after that Soma felt someone behind him once he turned around there was no one there, But before he could take another step he felt a presence and someone dropped a note near his foot, He knew who it was but it was unclear where she was at the moment but he knew she was somewhere near him, to him it was like she was using some kind of teleportation, however once the presence disappeared the contents of the note were quite urgent this is what it was written.

"Long time no see, soma well since you're being so persistent I'll tell you a little secret i might attack the human village, well maybe I will who knows? but you wouldn't trust your enemy would you.?.."

Soma crumbled the paper and gritted his teeth, he couldn't believe what he did just read, now he knew this was just a game to her, after he calmed down the two girls landed behind him and he decided to tell them about this note.

"She left a note near my foot while I tried to search for her, she said that she might attack the human village, but I don't know if she'll do that…"

Reimu clenched both her fists squeezing her purification rod tightly while Marisa got a little annoyed as well, next Reimu said.

"Does she think this is a game?"

The male simply nodded and then said to Reimu while sliding his sword inside it's sheath.

"Yes... She doesn't value any type of life, all she wants is power that is what turned into what she is now after all, she will betray all her allies if that means she'll get more power."

Reimu then noticed he knew a lot about this female, he was obviously hiding something he knew about this Youkai but she decided to ask it after she knew the human village was safe for sure, Reimu then flew towards to the human village with Marisa and Soma following her afterwards as the wind rushed past them making their air sway a lot, however a shadow appeared over Soma's eyes while he gritted his teeth, he was quite angry, once they arrived they landed in the middle of the village waiting for anything suspicious start happening, Reimu however had an idea, she knew would be better if they split up if they were lucky they could find the Youkai easily, so the female then said.

"Let's split up, we have a better chance of finding her if she attacks, if my theory is right that is."

Soma nodded and then he flew towards the south while Marisa flew towards the north and Reimu decided to fly towards the east, however none of them found someone suspicious after a while Soma started to think they were lied to he wasn't surprised however something happened, he was sure he saw some looking directly at him while wearing a cloak covering it's facial features, it was clear to Soma who it was judging by Reimu's theory it must have been her, however she disappeared once he heard some humans scream nearby, he then flew at the direction of the scream he saw a lot of humans running away, once he arrived where the commotion started he saw a blonde haired female however something was extremely off about her since she didn't move at the direction of the other humans, however she was holding a bloody Katana, once she saw Soma she jumped in the air and slashed at him Soma however managed to block the attack after he unsheathed his sword, making the blade clash against his, next the male slashed at the blonde at herculean speeds, however surprising enough it's reaction time and strength was very similar to his however this wasn't the only one attacking the village, there was another 2 nearby him, but Reimu and Marisa were nowhere to be found, since they were busy fighting their own opponents, it seemed they were organized to attack Reimu,Marisa and Soma in a 3v1 strategy and that would be a problem while Soma saw the other two puppets show up he said.

"Damn! This might be a problem; she seems to have gotten better at creating monsters!"

The male sighed and then the 3 of them attacked him at the same time the male could only defend their attacks there was no opening for him to attack, however he actually saw an opening and immediately flew behind her slashing the 3rd puppet on its back cutting it nearly in half however that didn't kill it, before he could attack another puppet the 1st puppet kicked his sword making him fly away, in the moment of distraction the male got kneed in the face making him crash into a house destroying part of it because of the impact dust flying up in the air, thankfully no one was inside the house, however before the dust settled, Soma flew from inside the dust at them at immense speeds cutting one of them in half destroying the puppet, he seemed to have a few scratches but his head was bleeding as well, he seemed to be a little different than before it was like he got more skilled, but that wasn't the case at all, the male then began to deflect the slashes made by the puppets, however something bad happened the both puppets attacked him at the same time he could only block one of the swords, so the male blocked one of the swords, however the other sword managed to hit him. drops of blood fell onto the floor, he had actually bitten into the of the 2nd puppet who attacked him breaking it, the male's mouth was cut a little however with immense force and speed he swung his katana while he saw the opening, cutting both puppets in half, destroying both of them. Once he knew they were defeated he panted while he cleaned some of the blood covering his eyes and said while breathing heavily.

"They are getting tougher… but they are still stupid."

Once he was done he was done with his enemies he flew towards the center of the village and he saw Reimu and Marisa, they seemed to be done fighting since they seemed to be talking to eachother, the male then landed close to them and said.

"It seems you were right Reimu, I think I saw her yet again.."

Reimu nodded and then they got surprised because he was quite hurt compared to them, because of that Marisa commented.

"Ya got yer ass kicked, are ya sure yer alright-ze?"

Soma nodded and then sighed, he was a bit glad they decided to help him, he knew he wouldn't be able to fight the Youkai he was trying to kill, however Reimu stroked the back of her head and sighed.

"Let's take him to the shrine… I need to talk about something else with him as well."

Reimu said while he looked at Marisa and Soma, the humans however were a bit afraid because now they knew now that them could get attacked at any moment, even though there weren't any casualties some of them were still hurt with deep wounds, once the three of them arrived in the shrine Reimu asked for Soma to follow her, without thinking twice he followed her inside her shrine, the then male sat down on the ground he asked while Marisa walked inside the house as well and sat down on top of one of the pillows near the table Reimu however looked at Soma and asked once all of them sat down and only her was standing up.

"You seem to know a lot about this Youkai… Too much in fact, I can tell you're not telling us a lot of stuff, now tell us everything."

Soma closed his eyes and sighed once the female asked that, he didn't want to speak about it but he knew maybe if he told them what he knew the information would help them find this Youkai.

"Alright I'll tell you two everything I know."

* * *

Well, here's the 2nd chapter sorry this took too long to write, Constructive Criticism is welcomed, also i'm a bit glad that some of you guys like the story, because of that i managed to think of how to continue this so look forward to more chapters.


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